Male sexual function consists of sexual desire, penile erection, ejaculation and extreme feeling. The penile erection is induced by gradual increase of the pressure within the penis. The internal pressure of the penis increases by the stimulation of the erectile nerve which leads to the expansion of sinusoids due to relaxation of smooth muscle of corpus cavernosum and increased blood flow due to the dilatation of arterioles. The internal pressure of the penis increases more by venous outflow blockage due to the compression of subtunical vein between a relatively hard tunica albuginea and sinusoids by expanded sinusoids.
According to statistics, about 20% to 60% of adult males suffer from sexual dysfunction, and the incidence thereof increases with age. Although these sexual dysfunctions were considered to occur mostly by psychogenic causes about 10 years ago, the development of modern medicine, reveals that the onset of sexual dysfunctions in about 50% or more of the sexual dysfunction patients is caused by other causes such as vascular, neurological and endocrine disorders, diabetics, hypertension, drug intake, etc.
Recently it is known that sildenafil (Viagra®), which has been developed as an oral agent for erectile dysfunction and used worldwide, shows a therapeutic effect on erectile dysfunction by increasing the concentration of cGMP by the inhibition of PDE-5 (phosphodiesterase-5) specifically distributed in the corpus cavernosum, which increases the blood flow in the corpus cavernosum, and thus inducing erection. In addition, PDE-5 inhibitors generally known as erectile dysfunction therapeutic agents include selective inhibitors of cyclic guanosine 3′,5′-monophosphate-specific phosphodiesterase type 5 (cGMP-specific PDE-5) such as Udenafil (C25H36N6O4S), Sildenafil (C22H30N6O4S), Vardenafil (C23H32N6O4S), Tadalafil (C22H19N3O4) and the like, which are disclosed in Korean Patent No. 0353014 (Udenafil), Korean Patent No. 0262926 (Sildenafil), Korean Patent No. 0430355 (Vardenafil), and Korean Patent No. 0357411 (Tadalafil). However, pre-existing drugs are reported to show various adverse events such as headache, facial flushing, dyspepsia, cardiac arrest, etc., and thus there is a need for a new drug that can replace or supplement the pre-existing drugs.
Therefore, it is required to develop a male sexual function-improving agent which does not show adverse events of pre-existing treatment methods and comprises a main ingredient which is not a chemically synthesized product but a natural substance. The clinical efficacy of natural products have been proven since long before and they generally show fewer adverse events than chemical substances, rendering them suitable candidates for the development of a composition for improving sexual function.
Ceriporia lacerata is a kind of white-rotting fungus and known to conduct co-metabolism, i.e., lignin decomposition, in order to use carbon sources such as cellulose, hemi-cellulose, other polysaccharides, and glycerol, etc., in the ecosystem. However, since Ceriporia lacerata was first reported to academic world in 2002, the research on the industrialization of Ceriporia lacerata has not been done sufficiently.
Accordingly, the present inventors have found that an extracellular polysaccharide produced by Ceriporia lacerata; a mycelial culture medium of Ceriporia lacerata containing the same, or dried powders or an extract thereof shows a sexual function-improving effect, and have completed the present invention which is related to a composition for improving sexual function comprising the extracellular polysaccharide, the mycelial culture medium, dried powders, or the extract, as an effective ingredient.